Congrats on the sucessful maiden. The SE is such a great flying plane, I love mine. The 12x6 would give you less verticle and more speed. Do you have the stock landing gear? If so, you'd have a hard time going to a 13 prop due to the ground clearance. You might try a 12x3 or 11x5. If you have the clearance though, I'd try a 13x5.